Coating compositions containing silane, methods for producing a coating composition and a coated substrate

ABSTRACT

A method for producing film-forming materials including resins and/or crosslinkers having a —Si(OR) 3  group. Methods of producing coating compositions and coating a substrate, such as a metal substrate, by electrodeposition. Applied coatings containing the film-forming materials can be cured to form crosslinked films on substrates.

BACKGROUND

Coating compositions are used in a variety of applications to coat avariety of substrates, often for protection of the substrate or toimprove adhesion of subsequent coating layers. Typical coatings includeelectrodeposition coatings, primers, sealers, basecoats, clearcoats, andone-coat topcoats. Coating compositions include film-forming materialscontaining one or more resins, which may be polymeric, oligomeric,and/or monomeric materials, that are applied to a substrate by variousmethods, including electrodeposition (or electrocoating), spray coating,dip coating, roll coating, knife coating, and curtain coating. As usedherein, a “resin” refers to one or more polymeric, oligomeric, and/ormonomeric materials; a polymer includes repeating monomer units; anoligomer is a polymer including a few repeating monomer units, typicallyten or fewer. Various types of film-forming materials are known andinclude epoxy, acrylic, polyurethane, polycarbonate, polysiloxane,aminoplast, and polyester resins.

Coating compositions can include a pigment dispersing or grind resin anda principal resin that generally constitutes the major polymeric part ofthe coating film. A grind resin usually includes a film-formingmaterial, with which a pigment paste is made by wetting out pigment,filler, and catalyst, such as a metal catalyst, where the grind resin isblended or mixed with the other materials by milling in, e.g., asandmill, ball mill, attritor, or other equipment. The pigment paste iscombined with the principal resin and, typically, a crosslinker; i.e.,curing agent. The grind resin and the principal resin can include thesame, different, or mixtures of various film-forming materials.

The relatively soft film of an applied coating composition can behardened by curing or crosslinking the film through incorporation of acrosslinker in the coating composition. The crosslinker can bechemically reactive toward the polymers, oligomers, and/or monomericcompounds of the resin in the coating composition, thereby covalentlyjoining the film-forming units together into a crosslinked film. Typicalcrosslinkers are activated (e.g., unblocked) using heat during a curingstep and/or by exposure to actinic radiation, Catalysts, such as metalcatalysts, can be used to facilitate thermal activation of thecrosslinker and the reaction of the crosslinker with the resin. Forexample, inclusion of a catalyst such as a metal catalyst can reduce therequisite cure temperature and/or provide for a more complete cure.

Coating compositions can be powder based, organic solvent based, oraqueous based However, it is often desirable to use aqueous basedcoatings in order to reduce organic emissions. Such aqueous coatingcompositions include emulsions and dispersions of cationic, anionic, ornonionic resins, which may be formed via the dispersive properties ofthe resins themselves or with aid of external surfactants.

Epoxy-based coatings include polymers, oligomers, and/or monomersprepared by reacting materials with epoxide groups with materials havingfunctional groups such as carboxyl, hydroxyl, and amine groups. Epoxiescan be cured or crosslinked to form hardened coatings by using variouscrosslinkers depending on the functional groups present. For example,hydroxy-functional resin can be cured using isocyanate compounds. Suchcoating compositions are known in the art; e.g., U.S. Pat. Nos.6,852,824; 5,817,733; and 4,761,337.

The electrodeposition process can be anodic or cathodic; typically thearticle to be coated serves as the cathode. Electrodeposition processesare advantageous both economically and environmentally due to the hightransfer efficiency of coating resin to the substrate and the low levelsof organic solvent, if any, that are employed. Another advantage ofelectrocoat compositions and processes is that the applied coatingcomposition forms a uniform and contiguous layer over a variety ofmetallic substrates regardless of shape or configuration. This isespecially advantageous when the coating is applied as an anticorrosivecoating onto a substrate having an irregular surface, such as a motorvehicle body. The even and continuous coating layer formed over allportions of the metallic substrate provides maximum anticorrosioneffectiveness.

Electrocoat baths can comprise an aqueous dispersion or emulsion of afilm-forming material, such as an epoxy resin, having ionicstabilization. A dispersion is typically a two-phase system of one ormore finely divided solids, liquids, or combinations thereof in acontinuous liquid medium such as water or a mixture of water and organiccosolvent. An emulsion is a dispersion of liquid droplets in a liquidmedium, preferably water or a mixture of water and various cosolvents.Accordingly, an emulsion is a type of dispersion.

For automotive or industrial applications, the electrocoat compositionsare formulated to be curable compositions by including a crosslinker.During electrodeposition, a coating composition containing anionically-charged resin is deposited onto a conductive substrate bysubmerging the substrate in an electrocoat bath having dispersed thereinthe charged resin and then applying an electrical potential between thesubstrate and a pole of opposite charge, for example, a stainless steelelectrode. The charged coating particles are plated or deposited ontothe conductive substrate. The coated substrate is then heated to curethe coating.

Typical substrates to be coated include metallic substrates, such assteel, galvanized and electrogalvanized metals, zinc alloys, andaluminum substrates. The substrate is often treated in a multi-stepprocess in order to prepare the surface prior to application of thecoating composition. Substrate preparation can include treatments withcleaners and conditioning rinses followed by phosphating (also known asphosphatizing or parkerizing) the substrate. For example, a steelsubstrate can be cleaned and conditioned to remove any metal workingfluids or oils by spraying with or immersion in cleaners andconditioning rinses. The cleaned substrate is then treated with a zinc,manganese, and/or iron phosphate conversion coating by immersion. Thephosphate coating serves to improve adhesion between the substrate andsubsequent organic coatings, such as an epoxy-based electrocoatingcomposition.

A significant amount of time and energy is involved in preparation ofthe coating composition, preparation of the substrate surface, and theapplication of the coating composition to the substrate. Elimination ofone or more steps or combination of multiple steps in the coatingprocess would be advantageous. Such changes could reduce the amount ofequipment necessary in addition to saving time and energy.

A need, therefore, exists for film-forming materials and processes usingfilm-forming materials that improve and simplify the coating process,for example, by reducing the number of steps involved and/or bycombining steps.

SUMMARY

The present invention provides a film-forming material comprising aresin, wherein the resin includes at least one pendent group comprisinga —Si(OR)₃ group, wherein each R is independently an alkyl groupincluding from 1 to about 12 carbon atoms or an aryl group includingsubstituted and unsubstituted phenyl and benzyl groups; and at least onecrosslinkable group. The crosslinkable group can be reactive with acrosslinker, self condensing, reactive with another group on the resin,or addition polymerizable. In some embodiments, the group reactive witha crosslinker can be an epoxide, hydroxyl, carboxyl, carbamate,aminoalkanol, aminoalkylether, amide, or amine group. The resin can beany film-forming resin, such as an epoxy, acrylic, polyurethane,polycarbonate, polysiloxane, aminoplast, or polyester resin and can be ahomopolymer or copolymer. In certain embodiments, the pendent group canbe bonded to the resin via an ester linkage and in various embodimentsthe pendent group further comprises a carboxylic acid group.

Further embodiments include a crosslinker for polymerizing afilm-forming material comprising an alkyl or aromatic compound includingat least two functional groups reactive with a film-forming material andat least one pendent group comprising a —Si(OR)₃ group, wherein each Ris independently an alkyl group including from 1 to about 12 carbonatoms or an aryl group including substituted and unsubstituted phenyland benzyl groups. Functional groups reactive with a film-formingmaterial include isocyanate, blocked isocyanate, uretdione, epoxide,hydroxyl, carboxyl, ester, ether, carbamate, aminoalkanol,aminoalkylether, amide, or amine groups.

In some embodiments, the film-forming material and/or the crosslinkercan further comprise a metal or metal compound coordinated by thefilm-forming material and/or crosslinker. The metal or metal compoundincludes those selected from a group consisting of M, MO, M₂O₃,M(OH)_(n), R_(x)MO, and combinations thereof; wherein, M is a metalselected from the group consisting of Al, Au, Bi, Ce, Cu, Fe, Pb, Sn,Sb, Ti, Y, Zn, and Zr; n is an integer satisfying the valency of M; R isan alkyl or aromatic group; and x is an integer from 1 to 6. In variousembodiments, the metal or metal compound comprises a metal catalystselected from a group consisting of dibutyltin oxide, dibutyltindilaurate, zinc oxide, bismuth oxide, tin oxide, yttrium oxide, copperoxide, and combinations thereof.

In various other embodiments, the film-forming material is produced by aprocess comprising reacting a resin having at least one pendent hydroxylgroup with a carboxylic anhydride having an ethylenically unsaturatedgroup to form a grafted resin having an ester group, a carboxylic acidgroup, and an ethylenically unsaturated group, wherein the resin has atleast one group reactive with a crosslinker. The ethylenicallyunsaturated group of the grafted resin is then reacted with a compoundhaving the formula HSi(OR)₃, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups,thereby producing a film-forming material having at least one pendentgroup comprising a —Si(OR)₃ group.

In some embodiments, a method of producing a coating compositionincludes combining a film-forming material and a crosslinker, whereinthe film-forming material comprises a resin having at least one pendentgroup comprising a —Si(OR)₃ group, wherein each R is independently analkyl group including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups; and atleast one crosslinkable group. In other embodiments, a method ofproducing a coating composition includes forming a film-forming materialby a process comprising: reacting a resin having at least one pendenthydroxyl group with a carboxylic anhydride having an ethylenicallyunsaturated group to form a grafted resin having an ester group, acarboxylic acid group, and an ethylenically unsaturated group, whereinthe resin has at least one crosslinkable group; and reacting theethylenically unsaturated group of the grafted resin with a compoundhaving the formula HSi(OR)₃, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups; andcombining a crosslinker and the film-forming material. Crosslinkers caninclude blocked polyisocyanate compounds, uretdione compounds,polyisocyanates and oligomers thereof, and combinations thereof.

In various other embodiments, methods of producing a coated substrateare provided. Methods include combining a crosslinker and a film-formingmaterial, the film-forming material comprising a resin, wherein theresin includes at least one pendent group comprising a —Si(OR)₃ group,wherein each R is independently an alkyl group including from 1 to about12 carbon atoms or an aryl group including substituted and unsubstitutedphenyl and benzyl groups; and at least one crosslinkable group; andapplying the coating composition to the substrate.

Some embodiments of producing a coated substrate include forming afilm-forming material by a process comprising reacting a resin having atleast one pendent hydroxyl group with a carboxylic anhydride having anethylenically unsaturated group to form a grafted polymer having anester group, a carboxylic acid group, and an ethylenically unsaturatedgroup, where the resin has at least one group reactive with acrosslinker. The ethylenically unsaturated group of the grafted polymeris reacted with a compound having the formula HSi(OR)₃, wherein each Ris independently an alkyl group including from 1 to about 12 carbonatoms or an aryl group including substituted and unsubstituted phenyland benzyl groups. A coating composition is prepared comprising acrosslinker and the film-forming resin and the coating composition isapplied to the substrate. Applying the various coating compositions caninclude electrodepositing the coating composition and in someembodiments the applied coating compositions are cured.

The present invention affords various benefits over conventionalfilm-forming resins. Such benefits include integration of the metalbinding characteristics of a phosphating treatment into the film-formingresin. Film-forming materials containing a resin having at least onependent group comprising a —Si(OR)₃ group exhibit improved adhesionbetween the resultant coating and a metallic substrate. Such resins canbe applied to an untreated metallic substrate surface, simplifyingand/or eliminating pretreatment steps. For example, these coatingcompositions can be applied to a substrate without the need for firstphosphating the substrate. The ability to forego the phosphatingtreatment saves considerable process time and energy and further savesconsiderable floor space required for phosphating immersion tanks andequipment.

The film-forming materials of the present invention can also coordinatemetals and metal compounds via the —Si(OR)₃ group. Such metals includemetallic substrates, metals on the surface of a substrate, and/or thecoordination of metal catalysts. The film-forming materials can furtherinclude other metal coordinating groups, such as carboxylic acid groups,that can also serve to coordinate metals and metal compounds.

The film-forming materials comprising a resin containing at least onependent group comprising a —Si(OR)₃ group can provide better adhesion toa metal substrate and/or better corrosion protection. Without wishing tobe bound by theory, it is believed that one or more oxygen atomscovalently bonded to the silicon atom in the film-forming resins caninteract with the metal substrate to enhance adhesion of the polymericfilm thereto. Furthermore, coating compositions according to the presentinvention can be formulated such that some of the pendent groups and/oradditional carboxylic acid groups can be coordinated with metalcatalysts to enhance curing of the coating, while other pendent groupsare free to interact with the metal substrate to enhance adhesion.

The ability to coordinate metal catalysts provides another advantage, inthat metal catalysts can reduce the requisite cure temperature of thecoating composition and/or provide for more complete curing. Thefilm-forming material can be mixed with various amounts of metalcatalysts to provide various amounts of resin-metal complexes using thecarboxylic acid groups and/or pendent groups from the resin. Forexample, the present invention enables liquid organometallic salts to beadded directly to the coating composition to form resin and metalcatalyst complexes.

“A” and “an” as used herein indicate “at least one” of the item ispresent; a plurality of such items may be present, when possible.“About” when applied to values indicates that the calculation or themeasurement allows some slight imprecision in the value (with someapproach to exactness in the value; approximately or reasonably close tothe value; nearly). If, for some reason, the imprecision provided by“about” is not otherwise understood in the art with this ordinarymeaning, then “about” as used herein indicates at least variations thatmay arise from ordinary methods of measuring or using such parameters.In addition, disclosure of ranges includes disclosure of all values andfurther divided ranges within the entire range.

DETAILED DESCRIPTION

Further areas of applicability and advantages will become apparent fromthe following description. It should be understood that the descriptionand specific examples, while exemplifying various embodiments of theinvention, are intended for purposes of illustration and are notintended to limit the scope of the invention.

The present invention includes film-forming materials, crosslinkers,processes for producing film-forming materials, coating compositions,methods of producing coating compositions, and methods of producingcoated substrates. Embodiments include at least one pendent groupcomprising a —Si(OR)₃ group, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups. One ormore of the oxygen atoms covalently bonded to the silicon atom cancoordinate metals and/or metal compounds, such as metal substratesand/or metal catalysts.

A film-forming material can comprise a resin, wherein the resin includesat least one pendent group comprising a —Si(OR)₃ group, wherein each Ris independently an alkyl group including from 1 to about 12 carbonatoms or an aryl group including substituted and unsubstituted phenyland benzyl groups. The resin also includes at least one crosslinkablegroup selected from a group reactive with a crosslinker, aself-condensing group, an addition polymerizable group, and a groupcurable with actinic radiation. The group reactive with a crosslinkercan be an epoxide, hydroxyl, carboxyl, carbamate, or amine group.

In one embodiment, the film-forming material comprises a resin thatincludes at least one pendent group comprising a —Si(OR)₃ group, and atleast one group reactive with a crosslinker. The resin can include oneor more polymeric, oligomeric, and/or monomeric materials. Thefilm-forming material can include various resins, such as epoxy,acrylic, polyurethane, polycarbonate, polysiloxane, polyvinyl,polyether, aminoplast, and polyester resins, and can include mixturesthereof. In embodiments where the resin is a polymer, it can be ahomopolymer or a copolymer. Copolymers have two or more types ofrepeating units.

In some embodiments, the pendent group comprising a —Si(OR)₃ group isbonded to the resin via various linkages. The pendent group can becovalently attached to the resin by ester, amine, urethane, and etherbonds, among others. Exemplary reactions of functional groups to producethese linkages include: epoxide reacted with acid resulting in an esterlinkage; epoxide reacted with amine resulting in an amine linkage;hydroxyl reacted with isocyanate resulting in a urethane linkage;hydroxyl reacted with anhydride resulting in an ester linkage; epoxidereacted with hydroxyl resulting in an ether linkage; and other types oflinkages generally used in forming coating resins.

Pendent groups can comprise a —Si(OR)₃ group, wherein each R isindependently an alkyl group including from 1 to about 12 carbon atomsor an aryl group including substituted and unsubstituted phenyl andbenzyl groups. Exemplary pendent groups can comprise trimethoxysilane,triethoxysilane, tripropoxysilane, tributoxysilane, tripentoxysilane,trihexoxysilane, triheptoxysilane, trioctoxysilane, trinonoxysilane,tridecoxysilane, triundecoxysilane, tridodecoxysilane, triphenoxysilane,and tribenzoxysilane groups.

In various embodiments, the pendent group can be added to the resinusing any one of several reactions. In one embodiment, a two-stepprocess is used to prepare a film-forming material comprising a resinhaving at least one pendent group comprising a —Si(OR)₃ group. In thefirst step, a resin, having at least one hydroxyl group and at least onegroup reactive with a crosslinker, is reacted with a carboxylicanhydride having an ethylenically unsaturated group to form a graftedresin having an ester linkage to a group comprising a carboxylic acidgroup and the ethylenically unsaturated group. Exemplary carboxylicanhydrides include aconitic anhydride, chloromaleic anhydride,citraconic anhydride, ethylmaleic anhydride, itaconic anhydride, maleicanhydride, mellitic anhydride, methoxymaleic anhydride, phthalicanhydride, pyromellitic anhydride, trimellitic anhydride,hexahydrophthalic anhydride, or tetrahydrophthalic anhydride. In thesecond step, the unsaturated carbon-carbon bond of the ethylenicallyunsaturated group of the grafted resin is then reacted with a compoundhaving the formula HSi(OR)₃, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups, tocovalently link the silicon atom to the resin.

Exemplary compounds having the formula HSi(OR)₃ comprisetrimethoxysilane, triethoxysilane, tripropoxysilane, tributoxysilane,tripentoxysilane, trihexoxysilane, triheptoxysilane, trioctoxysilane,trinonoxysilane, tridecoxysilane,

In some embodiments, the film-forming material comprising a —Si(OR)₃group can be formed, in part, by adapting the two-step graftingreactions as found in U.S. patent application Ser. No. 11/278,030 filedMar. 30, 2006, which is herein incorporated by reference. Thesereactions include various resins that are reacted with variousanhydrides. Various anhydrides include anhydrides having at least oneethylenically unsaturated group. The resin-anhydride reaction producthaving at least one ethylenically unsaturated group is reacted with anyone or more of various compounds having the formula HSi(OR)₃.

In some embodiments, a film-forming material comprises an epoxy resincomprising formula (1):

wherein, X¹ and X² are independently hydrogen, hydroxyl, epoxide, oramine functional monovalent radicals; each R¹, R², and R³ isindependently an organic divalent radical; each Y¹ is independently anorganic trivalent radical having from 1 carbon atom to about 36 carbonatoms; each Z¹ is independently a monovalent radical comprising—Si(OR)₃, wherein each R is independently an alkyl group including from1 to about 12 carbon atoms or an aryl group including substituted andunsubstituted phenyl and benzyl groups; n is an integer from 1 to about12; m is an integer from 0 to about 12; and p is an integer from 1 toabout 12.

In formula (1), the various values of m, n, and p correspond to resinshaving portions formed from various repeating monomer units. Thesevalues can be adjusted, for example, by varying the amounts and/orconcentrations of capping, chain terminating, or chain propagationgroups in the resin synthesis; where “capping” means a functional groupon the resin is reacted with a functional group of another molecule,such as an amine, to covalently bond the molecule to the resin.Furthermore, resin synthesis can be performed in steps or in batch, andtypically results in a mixed population of resin molecules havingvarious values for n, m, and p. The organic divalent radicals denoted byeach R¹, R², and R³ can be derived from the same molecule or can bedifferent molecules. Also, as shown in formula (1), when m is 0, thereis no R² group as the portion bracketed by m is absent. In this case, R³is covalently bonded to X².

In some embodiments, the organic divalent radicals denoted by R¹, R²,and R³ are 2,2-diphenylpropane divalent radicals. Furthermore, in caseswhere n>1, m>1, and/or p>1, two or more 2,2-diphenylpropylene radicalscan be linked to each other. For example, in some embodiments, R¹, R²,and/or R³ of the resin can comprise part of the product formed by thereaction of diglycidyl ether of bisphenol A (“G”) and bisphenol A (“B”),which results in repeats of the formula -G-B-. Embodiments furtherinclude permutations wherein n and p are integers from 1 to about 12 andm is an integer from 0 to about 12, resulting in repeating units such as-G-B-G-, -G-B-G-B-, -G-B-G-B-G-, and so on.

In some embodiments, X¹ and X² are independently hydrogen, hydroxyl,epoxide, or amine functional monovalent radicals. Embodiments of resinswhere X¹ and/or X² are amine monovalent radicals can include epoxyresins capped with an amine, where “capped” means a functional group onthe resin, such as an epoxide group, is reacted with theamine-containing compound to covalently bond the amine to the resin.Exemplary capping compounds can include ammonia or amines such asdimethylethanolamine, aminomethylpropanol, methylethanolamine,diethanolamine, diethylethanolamine, dimethylaminopropylamine, thediketamine derivative of diethylenetriamine, and mixtures thereof. Invarious embodiments, for example, a cathodic electrocoating compositioncan be formed by salting the (capped) amine-containing resin with anacid and dispersing it in water. Exemplary capping compounds alsoinclude aminoorganotrialkoxysilanes as disclosed elsewhere in thepresent teachings.

It should be noted that in some embodiments, such as for example, liquidepoxy coating compositions, the overall molecular weight of thefilm-forming material will affect the liquid phase properties, such asthe viscosity of the coating composition. Consequently, the molecularweight (and corresponding viscosity) of the resin can be adjusted asrequired by changing the number of repeating portions in the resin byvarying the values of n, m, and p in the above formula. For example,film-forming materials can include from one to about twelve unitsdenoted by both n and p and from zero to about twelve units denoted bym.

In some embodiments, the resin is a vinyl polymer, including an acrylicpolymer. The acrylic polymer comprises a functional group which is ahydroxyl, amino, or epoxy group that is reactive with a curing agent(i.e., crosslinker). Acrylic polymers can be formed using methylacrylate, acrylic acid, methacrylic acid, methyl methacrylate, butylmethacrylate, and cyclohexyl methacrylate. The functional group can beincorporated into the ester portion of the acrylic monomer. For example,hydroxyl-functional acrylic copolymers may be formed by polymerizationusing various acrylate and methacrylate monomers, including but notlimited to, hydroxyethyl acrylate, hydroxybutyl acrylate, hydroxybutylmethacrylate, or hydroxypropyl acrylate; amino-functional acryliccopolymers may be formed by polymerization with t-butylaminoethylmethacrylate and t-butylaminoethylacrylate; and epoxy-functional acryliccopolymers may be formed by reaction with glycidyl acrylate, glycidylmethacrylate, or allyl glycidyl ether.

Other ethylenically unsaturated monomers that may be used in forming theacrylic copolymer having reactive functionality include esters ornitriles or amides of alpha-, beta-ethylenically unsaturatedmonocarboxylic acids containing from 3 to 5 carbon atoms; vinyl esters,vinyl ethers, vinyl ketones, vinyl amides, and vinyl compounds ofaromatics and heterocycles. Representative examples further includeacrylic and methacrylic acid amides and aminoalkyl amides; acrylonitrileand methacrylonitriles; esters of acrylic and methacrylic acid,including those with saturated aliphatic and cycloaliphatic alcoholscontaining 1 to 20 carbon atoms such as methyl, ethyl, propyl, butyl,2-ethylhexyl, isobutyl, isopropyl, cyclohexyl, tetrahydrofurfuryl, andisobornyl acrylates and methacrylates; esters of fumaric, maleic, anditaconic acids, like maleic acid dimethyl ester and maleic acidmonohexyl ester; vinyl acetate, vinyl propionate, vinyl ethyl ether, andvinyl ethyl ketone; styrene, a-methyl styrene, vinyl toluene, and2-vinyl pyrrolidone.

Acrylic copolymers may be prepared by using conventional techniques,such as free radical polymerization, cationic polymerization, or anionicpolymerization, in, for example, a batch, semi-batch, or continuous feedprocess. For instance, the polymerization may be carried out by heatingthe ethylenically unsaturated monomers in bulk or in solution in thepresence of a free radical source, such as an organic peroxide or azocompound and, optionally, a chain transfer agent, in a batch orcontinuous feed reactor. Alternatively, the monomers and initiator(s)may be fed into the heated reactor at a controlled rate in a semi-batchprocess. Where the reaction is carried out in a solution polymerizationprocess, the solvent should preferably be removed after thepolymerization is completed. Preferably, the polymerization is carriedout in the absence of any solvent.

Typical free radical sources are organic peroxides such as dialkylperoxides, peroxyesters, peroxydicarbonates, diacyl peroxides,hydroperoxides, and peroxyketals; and azo compounds such as2,2′-azobis(2-methylbutanenitrile) and 1,1′-azobis(cyclohexanecarbonitrile). Typical chain transfer agents are mercaptanssuch as octyl mercaptan, n- or tert-dodecyl mercaptan, thiosalicyclicacid, mercaptoacetic acid, and mercaptoethanol; halogenated compounds,and dimeric alpha-methyl styrene. The free radical polymerization isusually carried out at temperatures from about 20° C. to about 250° C.,preferably from 90° C. to 170° C. The reaction is carried out accordingto conventional methods to produce a solid acrylic copolymer.

Acrylic resins can have an equivalent weight (grams resin solid per molequivalent —OH group) from about 150 to 950, including about 300 toabout 600, and further including about 350 to about 550. The numberaverage molecular weight (Mn) can be from about 5,000 to about 10,000for high solids. A typical acrylic polymer is a hydroxy functionalacrylic polyol. In some embodiments, an acrylic resin can be used toform an electrocoating composition. A cathodic electrocoatingcomposition may be formed by copolymerizing an amine-functionalethyleneically unsaturated monomer. The amine is salted and dispersed inwater.

In some embodiments, the resin is a polyester resin. Polyfunctional acidor anhydride compounds can be reacted with polyfunctional alcohols toform the polyester, and include alkyl, alkylene, arylalkylene, andaromatic compounds. Typical compounds include dicarboxylic acids andanhydrides; however, acids or anhydrides with higher functionality mayalso be used. If tri-functional compounds or compounds of higherfunctionality are used, these may be used in mixture withmono-functional carboxylic acids or anhydrides of monocarboxylic acids,such as versatic acid, fatty acids, or neodecanoic acid. Illustrativeexamples of acid or anhydride functional compounds suitable for formingthe polyester groups or anhydrides of such compounds include phthalicacid, phthalic anhydride, isophthalic acid, terephthalic acid,hexahydrophthalic acid, tetrachlorophthalic anhydride, hexahydrophthalicanhydride, pyromellitic anhydride, succinic acid, azeleic acid, adipicacid, 1,4-cyclohexanedicarboxylic acid, citric acid, and trimelliticanhydride.

The polyol component used to make the polyester resin has a hydroxylfunctionality of at least two. The polyol component may contain mono-,di-, and tri-functional alcohols, as well as alcohols of higherfunctionality. Diols are a typical polyol component. Alcohols withhigher functionality may be used where some branching of the polyesteris desired, and mixtures of diols and triols can be used as the polyolcomponent. However, in some cases, highly branched polyesters are notdesirable due to effects on the coating, such as decreased flow, andundesirable effects on the cured film, such as diminished chipresistance and smoothness.

Examples of useful polyols include, but are not limited to, ethyleneglycol, diethylene glycol, triethylene glycol, propylene glycol,dipropylene glycol, butylene glycol, glycerine, trimethylolpropane,trimethylolethane, pentaerythritol, neopentyl glycol,2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, and ethoxylated bisphenols.

Methods of making polyester resins are well-known. Polyesters aretypically formed by heating together the polyol and polyfunctional acidcomponents, with or without catalysts, while removing the by-product ofwater in order to drive the reaction to completion. A small amount of asolvent, such as toluene, may be added in order to remove the waterazeotropically. If added, such solvent is typically removed from thepolyester product before the coating formulation is begun.

In some embodiments, the resin can be a polyurethane resin.Polyurethanes can be formed from two components, where the firstincludes compounds containing hydroxyl groups, which are at leastdifunctional for the purposes of the isocyanate-addition reaction. Thesecond component includes at least one polyisocyanate compound.

The polyol component must be at least difunctional for the purpose ofthe polymerization reaction. These compounds generally have an averagefunctionality of about two to eight, preferably about two to four Thesecompounds generally have a molecular weight of from about 60 to about10,000, preferably from 400 to about 8,000. However, it is also possibleto use low molecular weight compounds having molecular weights below400. The only requirement is that the compounds used should not bevolatile under the heating conditions, if any, used to cure thecompositions.

Preferred macromonomer compounds containing isocyanate-reactive hydrogenatoms are the known polyester polyols, polyether polyols, polyhydroxypolyacrylates and polycarbonates containing hydroxyl groups. In additionto these polyhydroxy compounds, it is also possible to use polyhydroxypolyacetals, polyhydroxy polyester amides, polythioethers containingterminal hydroxyl groups or sulfhydryl groups or at least difunctionalcompounds containing amino groups, thiol groups or carboxyl groups.Mixtures of the compounds containing isocyanate-reactive hydrogen atomsmay also be used. Other exemplary hydroxyl containing compounds can befound in U.S. Pat. No. 4,439,593 issued on Mar, 27, 1984, which ishereby incorporated by reference.

In various embodiments, a film-forming material comprises formula (2):

wherein, R⁴ is a monovalent radical of a resin having from 2 to 12monomer units or a film-forming resin of formula (1); R⁵ is a monovalentradical of hydrogen, a resin having from 2 to 12 monomer units, or afilm-forming resin of formula (1); and Z² is a monovalent radicalcomprising —(CH₂)_(n)—Si(OR)₃, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups, and nis an integer from 1 to about 12.

Film-forming materials according to formula (2) further include thosewhere R⁴ and/or R⁵ are monovalent radicals of a resin, wherein the resinincludes at least one pendent group comprising a —Si(OR)₃ group, whereineach R is independently an alkyl group including from 1 to about 12carbon atoms or an aryl group including substituted and unsubstitutedphenyl and benzyl groups, and at least one crosslinkable group.

In some embodiments, film-forming materials include a resin that iscapped with an amine or aminoorganotrialkoxysilane; i.e., where afunctional group on the resin is reacted with the amine-containingcompound to covalently bond the amine to the resin. The resin can be anyresin as described, such as a resin including at least one pendent groupcomprising a —Si(OR)₃ group, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups, and atleast one group reactive with a crosslinker. In some embodiments, aminesand/or aminoorganotrialkoxysilanes can be used to cap a resin where theresin has at least one terminal epoxide group. Other resins can becapped, including resins not having a —Si(OR)₃ group, such as forexample where R⁴ and R⁵ in formula (2) do not have a —Si(OR)₃ group.These include epoxy, acrylic, polyurethane, polycarbonate, polysiloxane,aminoplast, or polyester resins. Further embodiments include cappingresins of formulas (1) and (2) with amines and/oraminoorganotrialkoxysilanes.

Suitable aminoorganotrialkoxysilanes for capping various resins includeH₂N—(CH₂)_(n)—Si(OR)₃, wherein each R is independently an alkyl groupincluding from 1 to about 12 carbon atoms or an aryl group includingsubstituted and unsubstituted phenyl and benzyl groups, and n is aninteger from 1 to about 12. Exemplary aminoorganotrialkoxysilanesinclude: beta-aminoethyltrimethoxysilane,beta-aminoethyltriethoxysilane, beta-aminoethyltributoxysilane,beta-aminoethyltripropoxysilane, alpha-aminoethyltrimethoxysilane,alpha-aminoethyltriethoxysilane, gamma-aminopropyltrimethoxysilane,gamma-aminopropyltriethoxysilane, gamma-aminopropyltributoxysilane,gamma-aminopropyltripropoxysilane, beta-aminopropyltrimethoxysilane,beta-aminopropyltriethoxysilane, beta-aminopropyltripropoxysilane,beta-aminopropyltributoxysilane, alpha-aminopropyltrimethoxysilane,alpha-aminopropyltriethoxysilane, alpha-aminopropyltributoxysilane,alpha-aminopropyltripropoxysilane,N-aminomethylaminoethyltrimethoxysilane,N-aminomethylaminomethyltripropoxysilane,N-aminomethyl-beta-aminoethyltrimethoxysilane,N-aminomethyl-beta-aminoethyltriethoxysilane,N-aminoethyl-beta-aminoethyltripropoxysilane,N-aminomethyl-gamma-aminopropyltrimethoxysilane,N-aminomethyl-gamma-aminopropytriethoxysilane,N-aminomethyl-gamma-aminopropyltripropoxysilane,N-aminomethyl-beta-aminopropyltrimethoxysilane,N-aminomethyl-beta-aminopropyltriethoxysilane,N-aminomethyl-beta-aminopropyltripropoxysilane,N-aminopropyltripropoxysilane, N-aminopropyltrimethoxysilane,N-(beta-aminoethyl)-beta-aminoethyltrimethoxysilane,N-(beta-aminoethyl)-beta-aminoethyltriethoxysilane,N-(beta-aminoethyl)-beta-aminoethyltripropoxysilane,N-(beta-aminoethyl)-beta-aminoethyltrimethoxysilane,N-(beta-aminoethyl)-alpha-aminoethyltriethoxysilane,N-(beta-aminoethyl)-alpha-aminoethyltripropoxysilane,N-(beta-aminoethyl)-beta-aminopropyltrimethoxysilane,N-(beta-aminoethyl)-gamma-aminopropyltriethoxysilane,N-(beta-aminoethyl)-gamma-aminopropyltripropoxysilane,N-(beta-aminoethyl)-gamma-aminopropyltrimethoxysilane,N-(beta-aminoethyl)-beta-aminopropyltriethoxysilane,N-(beta-aminoethyl)-beta-aminopropyltripropoxysilane,N-(gamma-aminopropyl)-beta-aminoethyltrimethoxysilane,N-(gamma-aminopropyl)-beta-aminoethyltriethoxysilane,N-(gamma-aminopropyl)-beta-aminoethyltripropoxysilane,N-methylaminopropyltrimethoxysilane,beta-aminopropylmethyldiethoxysilane,gamma-diethylenetriaminopropyltriethoxysilane,ureidopropyltrimethyloxysilane, andN-phenyl-3-aminopropyltriethoxysilane.

In some embodiments, the film-forming material can include a mixedpopulation of resin molecules. For example, the various reactionsdescribed can result in film-forming material products consisting offractions of various film-forming materials with different numbers ofrepeating monomer units. These film-forming materials can result fromvariations in the rate of propagation and termination events in thereaction used to form the resin and/or by adding various reactants instages.

In some embodiments, the film-forming material further comprises one ormore metals or metal containing compounds that are coordinated by theresin. The resin can coordinate the metal or metal containing compoundvia the pendent group comprising the —Si(OR)₃ group. In variousembodiments, the pendent group can further comprise a carboxylic acidgroup, allowing metal or metal compounds to be coordinated by the—Si(OR)₃ group and/or the carboxylic acid group. One or more oxygenatoms covalently bonded to the silicon atom can coordinate the metal ormetal compound. The carboxylic acid group can likewise coordinate ametal or metal compound via an oxygen atom. Metal coordination byfilm-forming materials is also described in U.S. patent application Ser.Nos. 11/553,185; 11/553,195; 11/553,213 filed Oct. 26, 2006; and Ser.No. 11/278,030 filed Mar. 30, 2006; which are herein incorporated byreference.

Film-forming materials can therefore coordinate one or more metals ormetal compounds, including metal substrates and/or metal catalysts thatimprove the cure response of the film-forming material when used in acoating composition. Metals and metal compounds can include thoseselected from a group consisting of M, MO, M₂O₃, M(OH)_(n), R_(x)MO, andcombinations thereof; wherein, n is an integer satisfying the valency ofM; R is an alkyl or aromatic group; and x is an integer from 1 to 6. Insome preferred embodiments, M is selected from the group consisting ofAl, Au, Bi, Ce, Cu, Fe, Pb, Sn, Sb, Ti, Y, Zn, and Zr. Exemplary metalcatalysts can include dibutyl tin oxide, dibutyl tin dilaurate, zincoxide, bismuth oxide, tin oxide, yttrium oxide, copper oxide, andcombinations thereof.

In some embodiments, a coating composition contains a crosslinker (i.e.,a curing agent) for polymerizing a film-forming material. Thecrosslinker comprises an organic compound including at least twofunctional groups reactive with a film-forming material and at least onependent group comprising a —Si(OR)₃ group, wherein each R isindependently an alkyl group including from 1 to about 12 carbon atomsor an aryl group including substituted and unsubstituted phenyl andbenzyl groups. Functional groups reactive with a film-forming resininclude isocyanate, blocked isocyanate, uretdione, epoxide, hydroxyl,carboxyl, ester, ether, carbamate, aminoalkanol, aminoalkylether, amide,or amine groups. Embodiments include derivatives of the variouscrosslinkers as disclosed elsewhere herein, where the crosslinker has atleast two functional groups reactive with a film-forming material and atleast one pendent group comprising a —Si(OR)₃ group.

In various embodiments, the pendent group of the crosslinker maycomprise the various pendent groups as described for a film-formingmaterial of the present teachings. In some embodiments, the crosslinkercan also coordinate a metal or metal compound via the pendent group.

In some embodiments, a crosslinker for polymerizing a film-formingmaterial comprises formula (3):

wherein, X³ and X⁴ are independently hydroxyl, epoxide, isocyanate,blocked isocyanate, or amine functional monovalent radicals; R⁶ and R⁷are independently organic divalent radicals; Y² is an organic trivalentradical having from 1 carbon atom to about 36 carbon atoms; and Z³ is amonovalent radical comprising —Si(OR)₃, wherein each R is independentlyan alkyl group including from 1 to about 12 carbon atoms or an arylgroup including substituted and unsubstituted phenyl and benzyl groups.

In some embodiments, a crosslinker includes a compound of formula (3)wherein R⁶ and R⁷ are 2,2-diphenylpropane divalent radicals.

In addition, various embodiments of the present crosslinkers can bemixed with various embodiments of the present film-forming materialsand/or with other resins to form coating compositions which can be usedto coat substrates. For example, a method of producing a coatedsubstrate comprises applying a coating composition comprising acrosslinker and a film-forming material, wherein one or both of thecrosslinker and the film-forming material includes a pendent groupcomprising a —Si(OR)₃ group, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups. Thecoating composition may be cured on the substrate.

Upon curing the present coating compositions, the resulting cured filmincludes the pendent group comprising a —Si(OR)₃ group, the silicon atomhaving three covalently bonded oxygen atoms, wherein one or more of theoxygen atoms can coordinate a metal or metal compound. The pendentgroups may be used to improve adhesion to and/or protection of a metalsubstrate In some embodiments, the crosslinkers comprising pendentgroups can be complexed with one or more metal catalysts prior toforming the coating composition or the metal catalyst can be added afterthe crosslinker is combined with the film-forming material.

The present invention provides various ways of producing a film-formingmaterial. In one embodiment, a film-forming material is produced by aprocess comprising reacting a resin having at least one pendent hydroxylgroup with a carboxylic anhydride having an ethylenically unsaturatedgroup to form a grafted resin having an ester group, a carboxylic acidgroup, and an ethylenically unsaturated group, wherein the resin has atleast one group reactive with a crosslinker; and reacting theethylenically unsaturated group of the grafted resin with a compoundhaving the formula HSi(OR)₃, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups.

The process of producing a film-forming material can further includeother reactants, such as capping agents, chain propagating or chainterminating agents, metals and metal compounds, and combinationsthereof. Exemplary molecules include bisphenol A, bisphenol F, diols,amines, phenol, and metals and metal compounds, including metalcatalysts.

The amount of pendent groups comprising a —Si(OR)₃ group incorporatedinto the resin can be varied and optimized for specific performancecharacteristics. In some embodiments, it is not necessary incorporatethe pendent groups throughout the backbone of the film-forming materialand/or have the majority of crosslinker molecules include the pendentgroups. In fact, in some embodiments, most of the polymer backboneand/or crosslinker molecules do not contain pendent groups comprising a—Si(OR)₃ group. The amount of pendent groups can be adjusted to provideenough pendent groups comprising a —Si(OR)₃ group, in order tocoordinate a metal and/or metal compound so that desired adhesioncharacteristics are realized and/or sufficient cure and/or coatingstability results. For example, in the case of an epoxy-based resin,from about 5% to about 15% of pendent hydroxyl groups can be reactedwith a carboxylic anhydride having an ethyleneically unsaturated groupand subsequently reacted with a compound having the formula HSi(OR)₃ toproduce a film-forming material.

Coating compositions of the present invention include the film-formingmaterials and/or crosslinkers as described. Methods of coatingsubstrates include application of coating compositions having thesefilm-forming materials and/or crosslinkers. Coated substrates havecoatings prepared from such coating compositions. Coating compositionscan be produced using epoxide, acrylic, polyurethane, polycarbonate,polysiloxane, aminoplast, and/or polyester resins, for example. Thesevarious resins can be formed by reactions of appropriate functionalgroups, as is known in the art, to produce the resin bond linkages. Suchreactions include: epoxide reacted with acid resulting in an esterlinkage; epoxide reacted with amine resulting in an amine linkage;hydroxyl reacted with isocyanate resulting in a urethane linkage;hydroxyl reacted with anhydride resulting in an ester linkage; epoxidereacted with hydroxyl resulting in an ether linkage; and other types oflinkages generally used in forming coating resins. The resultingfilm-forming resin contains a crosslinkable group, which can be a groupreactive with a crosslinker, a self-condensing group, an additionpolymerizable group, or a group curable with actinic radiation.Exemplary functional groups reactive with the film-forming resin includeisocyanate, blocked isocyanate, uretdione, epoxide, hydroxyl, carboxyl,ester, ether, carbamate, aminoalkanol, aminoalkylether, amide,aminoalkyl ethers, or amine groups.

In some embodiments, the film-forming material can comprise a vinyl oracrylic resin, wherein the vinyl resin has at least one pendent groupcomprising a —Si(OR)₃ group, wherein each R is independently an alkylgroup including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups, and atleast one group reactive with a crosslinker. The vinyl resin can beformed by polymerizing a compound having an unsaturated carbon bond anda pendent group comprising a —Si(OR)₃ group. Suitable compounds forincorporation during addition polymerization include the following:4-allyl-1,2-dimethoxybenzene; 2-allyl-2-methyl-1,3-cyclopentanedione;2-allyloxytetrahydropyran; allylphenyl carbonate; 3-allylrhodanine;allyltrimethoxysilane; itaconic anhydride; maleic anhydride; andcombinations thereof.

In various embodiments of producing a coating composition, thefilm-forming materials of the present invention can be the solefilm-forming resin, form a population of resins, or can be combined withadditional resins. The film-forming materials can be used as a grindresin, principal resin, and/or crosslinker. The same resin can be usedin preparing a pigment dispersion and the principal resin, or mixturesof various resins can be used to form a coating composition. In apigmented composition, the grind resin and the principal resin can becombined in forming a coating composition containing film-formingmaterial(s) according to the present invention.

Additional resins can be included with the film-forming materials of thepresent invention. For example, suitable additional resins include epoxyoligomers and polymers, such as polymers and oligomers of polyglycidylethers of polyhydric phenols such as bisphenol A. These can be producedby etherification of a polyphenol with an epihalohydrin or dihalohydrinsuch as epichlorohydrin or dichlorohydrin in the presence of alkali.Suitable polyhydric phenols include bis-2,2-(4-hydroxyphenyl)propane,bis-1,1-(4-hydroxyphenyl)ethane, bis(2-hydroxynaphthyl)methane and thelike. The polyglycidyl ethers and polyhydric phenols can be condensedtogether to form the oligomers or polymers. Other useful polyfunctionalepoxide compounds are those made from novolak resins or similarpoly-hydroxyphenol resins. Also suitable are polyglycidyl ethers ofpolyhydric alcohols such as ethylene glycol, propylene glycol,diethylene glycol and triethylene glycol. Also useful are polyglycidylesters of polycarboxylic acids which are produced by the reaction ofepichlorohydrin or a similar epoxy compound with an aliphatic oraromatic polycarboxylic acid such as succinic acid or terepthalic acid.

In some embodiments, an additional resin includes a liquid epoxy that isthe reaction product of diglycidyl ether of bisphenol A and bisphenol A.Examples include modified upgraded epoxy resins having epoxy equivalentweights of approximately 100 to 1200 or more. Suitable liquid epoxiesare GY2600, commercially available from Huntsman, and Epon® 828,commercially available from Hexion Specialty Chemicals, Inc. Forexample, epoxy-containing compounds can be reacted withhydroxyl-containing compounds, such as bisphenol A, ethoxylatedbisphenol A, phenol, polyols, or substituted polyols.

In various embodiments, coating compositions can also include a mixtureof resin compounds with groups reactive with a crosslinker (i.e., curingagent). The mixture of compounds can include more than one type of resinwith groups reactive with a crosslinker, a resin mixture with one ormore co-monomers, and more than one resin with at least one co-monomer.

In some embodiments, the present invention also includes incorporating ametal or a metal compound with the film-forming material to complex themetal or metal compound with the resin. Without wishing to be bound bytheory, one or more electron-rich oxygen atoms, such as an oxygen atombound to a silicon atom or an oxygen atom bound to a carbon atom (e.g.,an oxygen atom in a carboxylic acid group) may coordinate a metal ormetal compound through monodentate or polydentate geometries. Thus, thefilm-forming materials and associated metal(s) can form an associatedcomplex. Metals include the various metals, metal compounds, and metalcatalysts already mentioned. The metal can be added to the film-formingmaterial, crosslinker, or to both the film-forming material andcrosslinker, for example. In some embodiments, the metal catalyst isincorporated in a coating composition prior to curing the resin andcrosslinker to form a cured coating. Alternatively, the metal catalystcan be incorporated with the film-forming material as a subpart of acoating composition; for example, the metal catalyst can be added to afilm-forming material used as a grind resin.

A metal catalyst can also be incorporated at other various steps inproducing the film-forming material. In some embodiments, the metalcatalyst is incorporated in the step of forming the film-formingmaterial, i.e., as the film-forming material is formed by the variousreactions and mixtures described herein. Alternatively, the metalcatalyst can be incorporated with the film-forming material after theresin is formed and prior to the reaction of the resin and thecrosslinker to form the cured coating. For instance, in someembodiments, a pigment-containing composition may be incorporated priorto the step of reacting (i.e., curing) the resin and the crosslinker.Coating compositions commonly incorporate such pigment-containingcompositions. The metal catalyst can be incorporated into thepigment-containing composition to complex the metal catalyst with thefilm-forming material.

Embodiments can include one metal catalyst, or in some embodiments, acombination of metal catalysts can be employed. The metal catalysts,such as for example, various metal oxides, can be supplied in a milledform having a low particle size (e.g., less than 20 microns, moretypically less than 10 microns) such that no additional grinding isneeded to reduce the particle size of the metal catalyst for effectiveincorporation of the metal catalyst with the film-forming materialand/or crosslinker.

Various coating compositions include polyisocyanate crosslinkers capableof reacting with the film-forming material. Polyisocyanate crosslinkerscan comprise any desired organic polyisocyanate having free isocyanategroups attached to aliphatic, cycloaliphatic, araliphatic and/oraromatic structures. Polyisocyanates can have from 2 to 5 isocyanategroups per molecule. Exemplary isocyanates are described in “Methodender organischen Chemie” [Methods of Organic Chemistry], Houben-Weyl,volume 14/2, 4th Edition, Georg Thieme Verlag, Stuttgart 1963, pages 61to 70, and by W. Siefken, Liebigs Ann. Chem. 562, 75 to 136. Suitableexamples include 1,2-ethylene diisocyanate, 1,4-tetramethylenediisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4- and2,4,4-trimethyl-1,6-hexamethylene diisocyanate, 1,12-dodecanediisocyanate, omega,omega′-diisocyanatodipropyl ether, cyclobutane1,3-diisocyanate, cyclohexane 1,3- and 1,4-diisocyanate, 2,2- and2,6-diisocyanato-1-methylcyclohexane,3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophoronediisocyanate), 2,5- and3,5-bis(isocyanatomethyl)-8-methyl-1,4-methano-decahydronaphthalene,1,5-, 2,5-, 1,6- and2,6-bis(isocyanatomethyl)-4,7-methanohexahydroindane, 1,5-, 2,5-, 1,6-and 2,6-bis(isocyanato)-4,7-methylhexahydroindane, dicyclohexyl2,4′- and4,4′-diisocyanate, 2,4- and 2,6-hexahydrotolylene diisocyanate, perhydro2,4′- and 4,4′-diphenylmethane diisocyanate,omega,omega′-diisocyanato-1,4-diethylbenzene, 1,3- and 1,4-phenylenediisocyanate, 4,4′-diisocyanatobiphenyl,4,4′-diisocyanato-3,3′-dichlorobiphenyl,4,4′-diisocyanato-3,3′-dimethoxybiphenyl,4,4′-diisocyanato-3,3′-dimethylbiphenyl,4,4′-diisocyanato-3,3′-diphenylbiphenyl, 2,4′- and4,4′-diisocyanatodiphenylmethane, naphthylene-1,5-diisocyanate, tolylenediisocyanates, such as 2,4- and 2,6-tolylene diisocyanate,N,N′-(4,4′-dimethyl-3,3′-diisocyanatodiphenyl)uretdione, m-xylylenediisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylylenediisocyanate, but also triisocyanates, such as2,4,4′-triisocyanatodiphenyl ether, 4,4′,4″-triisocyanatotriphenylmethane. Polyisocyanates can also contain isocyanurate groups and/orbiuret groups and/or allophanate groups and/or urethane groups and/orurea groups. Polyisocyanates containing urethane groups, for example,are obtained by reacting some of the isocyanate groups with polyols, forexample trimethylol propane and glycerol. Examples of suitablecrosslinkers include: unblocked and blocked polyisocyanate compoundssuch as self-blocking uretdione compounds; caprolactam-and oxime-blockedpolyisocyanates; isocyanurates of diisocyanates; diisocyanateshalf-blocked with polyols; and combinations thereof.

Polyisocyanate crosslinkers can further include polymeric MDI, anoligomer of 4,4′-diphenylmethane diisocyanate, or other polyisocyanatethat is blocked with an ethylene glycol ether or a propylene glycolether. Such crosslinkers containing urethane groups can be prepared, forexample, from Lupranate® M20S, or other similar commercially availablematerials. Polyisocyanate compounds are commercially available from,among others, BASF AG, Degussa AG, and Bayer Polymers, LLC.

In some embodiments, thermal curing can include the reaction betweenisocyanate (free or blocked) with an active hydrogen functional groupsuch as a hydroxyl or a primary or secondary amine; or that between anaminoplast and an active hydrogen material such as a carbamate, urea,amide or hydroxyl group; an epoxy with an active hydrogen material suchas an acid, phenol, or amine; a cyclic carbonate with an active hydrogenmaterial such as a primary or secondary amine; a silane (i.e., Si—O—Rwhere R═H, an alkyl or aromatic group, or an ester) with an activehydrogen material, including when the active hydrogen material is Si—OH,as well as mixtures of these crosslinking pairs.

In various embodiments, methods of producing a coating composition canfurther comprise forming a salting site on the film-forming material.The film-forming materials can be further reacted with an aminecontaining compound, such as methylaminoethanol, diethanol amine, or thediketamine derivative of diethylenetriamine, to provide a salting siteon the resin for use in cathodic electrocoating. Alternatively,quaternium ammonium, sulfonium, or phosphonium sites can beincorporated. Or, the film-forming materials can be reacted with an acidfunctionality in order to make anodic electrocoating compositions oranionic aqueous coating compositions.

These salting sites are then reacted, or salted, in forming an aqueousdispersion in forming electrodepositable or other aqueous coatingcompositions, for example. The film-forming material can have basicgroups salted with an acid for use in a cathodic electrocoatingcomposition. This reaction may be termed neutralization or acid-saltingand specifically refers to the reaction of pendent amino or quarternarygroups with an acidic compound in an amount sufficient to neutralizeenough of the basic amino groups to impart water-dispersibility to theresin. Illustrative acid compounds can include phosphoric acid,propionic acid, acetic acid, lactic acid, formic acid, sulfamic acid,alkylsulfonic acids, and citric acid. Or, an acidic resin can be saltedwith a base to make an anodic electrocoating composition. For example,ammonia or amines such as dimethylethanolamine, triethylamine,aminomethylpropanol, methylethanolamine, and diethanolamine can be usedto form an anodic electrocoating composition.

In some embodiments, coating compositions can also include at least oneadditive. Many types of additives are known to be useful in coatingcompositions, including electrocoating compositions. Such additives caninclude various organic solvents, surfactants, dispersants, additives toincrease or reduce gloss, catalysts, pigments, fillers, and saltingagents. Additional additives further include hindered amine lightstabilizers, ultraviolet light absorbers, anti-oxidants, stabilizers,wetting agents, rheology control agents, adhesion promoters, andplasticizers. Such additives are well-known and may be included inamounts typically used for coating compositions.

In some embodiments, the film-forming materials can be used in methodsof producing aqueous coating compositions The aqueous medium of acoating composition is generally predominantly water, but a minor amountof organic solvent can be used. Examples of useful solvents include,without limitation, ethylene glycol butyl ether, propylene glycol phenylether, propylene glycol propyl ether, propylene glycol butyl ether,diethylene glycol butyl ether, dipropylene glycol methyl ether,propylene glycol monomethyl ether acetate, xylene, N-methylpyrrolidone,methyl isobutyl ketone, mineral spirits, butanol, butyl acetate,tributyl phosphate, dibutyl phthalate, and so on. However, organicsolvent can be avoided to minimize organic volatile emissions from thecoating process.

Examples of suitable surfactants include, without limitation, thedimethylethanolamine salt of dodecylbenzene sulfonic acid, sodiumdioctylsulfosuccinate, ethoxylated nonylphenol, sodium dodecylbenzenesulfonate, the Surfynol® series of surfactants (Air Products andChemicals, Inc.), and Amine-C (Huntsman Corp.). Generally, both ionicand non-ionic surfactants may be used together, and, for example, theamount of surfactant in an electrocoat composition may be from 0 to 2%,based on the total solids. Choice of surfactant can also depend on thecoating method. For example, an ionic surfactant should be compatiblewith the particular electrocoating composition, whether it is cathodicor anodic.

When the coating composition is a primer composition or pigmentedtopcoat composition, such as a basecoat composition, one or morepigments and/or fillers may be included. Pigments and fillers may beutilized in amounts typically of up to about 40% by weight, based ontotal weight of the coating composition. The pigments used may beinorganic pigments, including metal oxides, chromates, molybdates,phosphates, and silicates. Examples of inorganic pigments and fillersthat could be employed are titanium dioxide, barium sulfate, carbonblack, ocher, sienna, umber, hematite, limonite, red iron oxide,transparent red iron oxide, black iron oxide, brown iron oxide, chromiumoxide green, strontium chromate, zinc phosphate, silicas such as fumedsilica, calcium carbonate, talc, barytes, ferric ammonium ferrocyanide(Prussian blue), ultramarine, lead chromate, lead molybdate, and micaflake pigments. Organic pigments may also be used. Examples of usefulorganic pigments are metallized and non-metallized azo reds,quinacridone reds and violets, perylene reds, copper phthalocyanineblues and greens, carbazole violet, monoarylide and diarylide yellows,benzimidazolone yellows, tolyl orange, naphthol orange, and the like.

Coating compositions formed according to the methods described can becoated on a substrate by any of a number of techniques well-known in theart. These can include, for example, spray coating, dip coating, rollcoating, curtain coating, knife coating, coil coating, and the like. Insome embodiments, the coating composition of the invention can beelectrodepositable and can be coated onto the substrate byelectrodeposition. The electrodeposited or applied coating layer can becured on the substrate by reaction of the resin and crosslinker.

The coating composition can be electrodeposited as is conventionallyperformed in the art Electrodeposition includes immersing anelectrically conductive article in an electrocoating bath containing acoating composition of the present teachings, connecting the article asthe cathode or anode, preferably as the cathode, depositing a coatingcomposition film on the article using direct current, removing thecoated article from the electrocoating bath, and subjecting thedeposited electrocoated material film to conventional thermal curing,such as baking.

Coating compositions of the present invention are also useful as coilcoatings. Coil coatings are applied to coiled sheet metal stock, such assteel or aluminum, in an economical, high speed process. The coilcoating process results in a high quality, uniform coating with littlewaste of the coating and little generation of organic emissions ascompared to other coating methods, e.g. spray application.

Polyester resins can be used as coil coating compositions and cancomprise a branched polyester and/or an essentially linear polyester anda crosslinker. A pendent group comprising a —Si(OR)₃ group, wherein eachR is independently an alkyl group including from 1 to about 12 carbonatoms or an aryl group including substituted and unsubstituted phenyland benzyl groups, can be incorporated into the polyester and/or thecrosslinker. The branched polyester can be prepared by condensation of apolyol component and a polyacid component, either of which can furtherinclude the pendant group or be reactive with a compound comprising thependent group. The polyester synthesis may be carried out undersuitable, well-known conditions, for example at temperatures from about150° C. to about 250° C., with or without catalyst (e g., dibutyl tinoxide, tin chloride, butyl chlorotin dihydroxide, ortetrabutyoxytitanate), typically with removal of the by-product water(e.g., by simple distillation, azeotropic distillation, vacuumdistillation) to drive the reaction to completion. The crosslinker canhave groups reactive with the hydroxyl functionality of the polyesters.Suitable crosslinkers include, without limitation, aminoplasts andisocyanate crosslinking agents. The coil coating composition typicallyfurther includes a pigment and can contain other additives and fillers.

Coil coating is a continuous feeding operation, with the end of one coiltypically being joined (e.g., stapled) to the beginning of another coil.The coil is first fed into an accumulator tower and coating is fed intoan exit accumulator tower, with the accumulator towers allowing thecoating operation to continue at constant speed even when intake of thecoil is delayed. For example, coil advancement can be delayed to start anew roll, or for winding of the steel, for example, to cut the steel toend one roll and begin a new roll. The coil is generally cleaned toremove oil or debris, pre-treated, primed with a primer on both sides,baked to cure the primer, quenched to cool the metal, and then coated onat least one side with a topcoat. A separate backer or a differenttopcoat may be applied on the other side. The topcoat is baked andquenched, then fed into the exit accumulator tower and from there isre-rolled.

The coating compositions can be applied onto many different substrates,including metal substrates such as bare steel, phosphated steel,galvanized steel, gold, or aluminum; and non-metallic substrates, suchas plastics and composites including an electrically conductive organiclayer. In electrocoating (e.g., electrodeposition) or electrospray, onlyelectrically conductive substrates are used. The substrate may also beany of these materials having upon it already a layer of anothercoating, such as a layer of an electrodeposited primer, primer surfacer,and/or basecoat, either cured or uncured. When the substrate ismetallic, the film-forming material with a pendent group comprising a—Si(OR)₃ group can act to improve film adhesion to the substrate.

Although various methods of curing may be used, in some embodiments,thermal curing can be used. Generally, thermal curing is effected byheating at a temperature and for a length of time sufficient to causethe reactants (i.e., the film-forming material and crosslinker) to forman insoluble polymeric network. The cure temperature can be from about150° C. to about 200° C. for electrocoating compositions, and the lengthof cure can be about 15 minutes to about 60 minutes. Cure temperaturescan be lower, for example, and in some embodiments can be reduced to140° C. or lower due to metal catalysts complexed to the pendent groupsin the film-forming materials. Therefore, lower bake temperatures can beused in some instances. For topcoats, the cure temperature can be fromabout 120° C. to about 140° C. and the cure time can be about 15 minutesto about 30 minutes. Heating can be done in infrared and/or convectionovens.

A coil coating composition cures at a given peak metal temperature. Thepeak metal temperature can be reached more quickly if the oventemperature is high. Oven temperatures for coil coating generally rangefrom about 220° C. to about 500° C., to obtain peak metal temperaturesof between 180° C. and about 250° C., for dwell times generally rangingfrom about 15 seconds to about 80 seconds. Oven temperatures, peak metaltemperature and dwell times are adjusted according to the coatingcomposition, substrate, and level of cure desired. Examples of coilcoating methods are disclosed in U.S. Pat Nos. 6,897,265; 5,380,816;4,968,775; and 4,734,467, which are incorporated herein by reference.

The film-forming materials, crosslinkers, coating compositions, andmethods of the present invention provide several advantages. Forexample, pretreatment of metal surfaces, such as phosphating, can beeliminated due to increased adhesion and corrosion performance ofcoating compositions made according to present teachings. Increasedadhesion can be due to complexes forming between the pendent groupsincorporated in the film-forming material (and/or crosslinker) and themetal substrate. Elimination of the phosphating step in coating a steelsubstrate can save time and expense. Furthermore, complexing metalcatalysts with the film-forming material can improve cure response andcatalytic efficiency of the applied coating composition. Theseimprovements can be effected by the proximity of the metal catalyst tothe reactive functional groups in the crosslinking matrix.

The present technology is further described in the following example.The example is merely illustrative and does not in any way limit thescope of the technology as described and claimed. All parts given areparts by weight unless otherwise noted. Tradename compounds suitable forpracticing embodiments of the technology may be included, whereapplicable.

EXAMPLE 1 Synthesis of a Film-Forming Resin Containing Silane

A film-forming resin, having at least one pendent group comprising a—Si(OR)3 group, is formed using a four step process. The first step isthe backbone synthesis of the resin polymer. Diglycidyl ether ofbisphenol A, bisphenol A, solvent, phenol, and catalyst are combined andreacted to produce a hydroxy polymer with monomer unit linkagescontaining a hydroxyl group flanked by ethers. The second step is aminecapping by reacting the hydroxy polymer with primary or secondaryamines, including aminoorganotrialkoxysilanes to incorporate —Si(OR)₃groups. The third step involves a graft reaction between the cappedhydroxy polymer and a carboxylic anhydride, where the carboxylicanhydride has an ethylenically unsaturated group. The carboxylicanhydride reacts with the hydroxyl group of the polymer producing anester linkage between the former anhydride and the polymer. The graftedpolymer product includes a carboxylic acid group and the ethylenicallyunsaturated group. The fourth step is reaction of the ethylenicallyunsaturated nucleophile with a compound having the formula HSi(OR)₃,wherein each R is independently an alkyl group including from 1 to about12 carbon atoms or an aryl group including substituted and unsubstitutedphenyl and benzyl groups.

The film-forming resin containing —Si(OR)₃ groups coordinates metals viaone or more oxygen atoms covalently bonded to the silicon atom and/orthe carboxylic acid groups. Metal coordination includes metals from asubstrate surface, when the resin is applied as a coating film, andmetals and metal compounds in the form of metal catalysts added to thecoating composition to enhance cure properties of the coating film.

The synthesis scheme is illustrated as follows:

In the synthesis scheme, R¹ and R² are organic groups incorporated bycapping with the secondary amine and R³ is an organic group incorporatedfrom the aminoorganotrialkoxysilane. M is a metal from a metal substrateto which the film-forming material is applied, or M is a metal or metalcompound, such as a metal catalyst. M includes the following metalspecies: M, MO, M₂O₃, M(OH)_(n), R_(x)MO, and combinations thereof;wherein, M is a metal selected from the group consisting of Al, Bi, Ce,Cu, Fe, Pb, Sn, Sb, Ti, Y, Zn, and Zr; n is an integer satisfying thevalency of M; R is an alkyl or aromatic group; and x is an integer from1 to 6.

The description of the technology is merely exemplary in nature and,thus, variations that do not depart from the gist of the presentinvention are intended to be within the scope of the invention. Suchvariations are not to be regarded as a departure from the spirit andscope of the invention.

1. A method of producing a coating composition comprising: forming afilm-forming material by a process comprising: reacting a resin havingat least one pendent hydroxyl group with a carboxylic anhydride havingan ethylenically unsaturated group to form a grafted resin having anester group, a carboxylic acid group, and an ethylenically unsaturatedgroup, wherein the resin has at least one crosslinkable group; andreacting the ethylenically unsaturated group of the grafted resin with acompound having the formula HSi(OR)₃, wherein each R is independently analkyl group including from 1 to about 12 carbon atoms or an aryl groupincluding substituted and unsubstituted phenyl and benzyl groups; andcombining a crosslinker and the film-forming material.
 2. A method ofclaim 1, wherein the crosslinkable group is a group reactive with acrosslinker, a self-condensing group, an addition polymerizable group,or a group curable with actinic radiation.
 3. A method of claim 1,wherein the crosslinkable group is an epoxide, hydroxyl, carboxyl,carbamate, isocyanate, blocked isocyanate, or amine group.
 4. A methodof claim 1, wherein the resin is an epoxy, acrylic, polyurethane,polycarbonate, polysiloxane, polyvinyl, polyether, aminoplast, orpolyester resin.
 5. A method of claim 1, wherein the resin is a productof a reaction comprising diglycidyl ether of bisphenol A and bisphenolA.
 6. A method of claim 1, further comprising: capping the resin byreacting the resin with an amine or aminoorganotrialkoxysilane, whereinthe resin has at least one terminal epoxide group.
 7. A method of claim1, further comprising: capping the resin by reacting the resin withH₂N—(CH₂)_(n)—Si(OR)₃, wherein each R is independently an alkyl groupincluding from 1 to about 12 carbon atoms or an aryl group includingsubstituted and unsubstituted phenyl and benzyl groups, n is an integerfrom 1 to about 12; and the resin has at least one terminal epoxidegroup.
 8. A method of claim 1, wherein the carboxylic anhydride havingan ethylenically unsaturated group comprises from 4 to about 36 carbonatoms.
 9. A method of claim 1, wherein the carboxylic anhydride isaconitic anhydride, chloromaleic anhydride, citraconic anhydride,ethylmaleic anhydride, itaconic anhydride, maleic anhydride, melliticanhydride, methoxymaleic anhydride, phthalic anhydride, pyromelliticanhydride, trimellitic anhydride, hexahydrophthalic anhydride, ortetrahydrophthalic anhydride.
 10. A method of claim 1, wherein thecrosslinker is selected from a group consisting of blockedpolyisocyanate compounds, uretdione compounds, polyisocyanates andoligomers thereof, and combinations thereof.
 11. A method of claim 1,wherein the crosslinker comprises an alkyl or aromatic compoundincluding at least two functional groups reactive with a film-formingmaterial and at least one pendent group comprising a —Si(OR)₃ group,wherein each R is independently an alkyl group including from 1 to about12 carbon atoms or an aryl group including substituted and unsubstitutedphenyl and benzyl groups.
 12. A method of claim 1, further comprising:forming a salting site on the film-forming material by reacting the filmforming material with an amine; incorporating quaternium ammonium,sulfonium, or phosphonium functionality on the film-forming material; orincorporating an acid functionality.
 13. A method of claim 12, whereinthe amine is selected from a group consisting of diethanolamine,methylethylanolamine, diketamine of diethylenetriamine, and combinationsthereof.
 14. A method of claim 1, wherein the combining step furtherincludes at least one member of a group consisting of pigment, saltingagent, metal or metal compound, and combinations thereof.
 15. A methodof claim 14, wherein the metal or metal compound is selected from agroup consisting of M, MO, M₂O₃, M(OH)_(n), R_(x)MO, and combinationsthereof; wherein, M is a metal selected from the group consisting of Al,Au, Bi, Ce, Cu, Fe, Pb, Sn, Sb, Ti, Y, Zn, and Zr; n is an integersatisfying the valency of M; R is an alkyl or aromatic group; and x isan integer from 1 to
 6. 16. A method of claim 14, wherein the metal ormetal compound comprises a metal catalyst selected from a groupconsisting of dibutyltin oxide, dibutyltin dilaurate, zinc oxide,bismuth oxide, tin oxide, yttrium oxide, copper oxide, and combinationsthereof.